Feb 19, 2013 8:00am PST
student at city college in san francisco in 1980. got into conceptual physics, it spurred her on. today, she is a design engineer at jet propulsion labs in california at pasadena, and she is working on these fly-by missions and all that stuff and right now she is doing what, you are making a pod to fly in the next space shuttle, and that's what she is doing, okay? tinnie, hold these up and then tell me which of those two has the most mass? they feel the same to me. these are the same weight gang, okay? but i want you to do something else tinnie. i want you to hold it at the midpoint, and then rotate it like this. and now try this one. any difference? this is hard to rotate. very much hard. take them both and do it. like something up here? yeah, you can really feel the difference. let's try this. put this in your hand, flip that like this, you do like this, flip it. okay, now change gang, now change. oh-oh-oh-oh huh? guess how the lead is distributed inside here, thanks very much, tinnie. guess how the lead is distributed, gang. guess where it's closer to the center. take a guess. they'r
Feb 13, 2013 8:00am PST
this thing, we could generate electricity to light up cities. and sure enough, we do. and we have devices like this. and we put a waterfall over here and turn it, use the energy of that waterfall, potential, kinetic, rotational, mechanical, off it goes this light, huh? do that, or we could put a steam turbine here, direct some expanding steam against the turbine, against the paddle wheel and turn it. and so our civilization really rests on devices like this. but there's gotta be some energy input to be transformed over here. now, here's a neat little thing. when i turn this and i unscrew the lamp, it becomes easier to turn. easier to turn. why? well, when it's unhooked, there's no energy going off. and so what i'm turning against now is a friction. but when it's hooked up, i'm pushing against the friction plus the electricity. so let's--i can show you that. can i have a volunteer? could you come up here, please? what i'm gonna do-- you stand over here, and what i want you to do-- i'm not gonna look, i'm gonna look over here, okay? and i want you to unscrew that, and i'll tell you when it'